Very little is known about the genetic organization, transcription, translation and insertion of integral plasma membrane proteins. Bacteriorhodopsin is a very well characterized integral membrane protein produced by Halobacterium halobium. H. halobium is grown under conditions that either do or do not lead to the induction of bacteriorhodopsin. Techniques for successfully isolating and characterizing ribosomal and mRNA are compared and appropriate in vitro translation systems are tested for the ability to translate H. halobium message, in general, and bacteriohodopsin messenger in particular. The latter is identified by immunoprecipitation with specific antibodies which have been developed. From this starting point, the gene, messenger and initial translation product for bacteriorhopsin will be characterized. The ability to insert the in vitro synthesized peptide will allow us to determine the characteristics and, hopefully, the mechanism of protein insertion and membrane assembly.